The present invention relates to a housing structure for an optical scanning system of an imaging device for scanning the peripheral surface of a photoconductive member with a laser beam modulated based on image data and deflected by a dynamic deflecting means, such as a polygonal mirror, and forming an image on a recording paper with employing an electrophotographic process, wherein optical elements relating to the scanning operation effected by the laser beam are disposed in the housing structure with a predetermined positional relationship.
There are imaging devices employing an electrophotographic process for providing a hard copy by printing or drawing data output from a computer, word processor, facsimile and the like on a recording paper.
The electrophotographic process is such that a photoconductive material on the surface of a photoconductive member is uniformly charged, a latent image is formed by a portion of the photoconductive material from which electric charges are removed by exposure. The latent image is developed by adhering toner thereto (made to a toner image), and then the thus obtained toner image is transferred to a recording paper and further fixed thereon by a fixing unit.
One of such imaging devices employs an optical scanning system for causing the light beam carrying image data to perform a scanning and exposing operation. One of the optical scanning systems is a laser scanning system which is arranged such that a laser beam emitted from a semiconductor laser and corresponding to an input signal is irradiated onto a photoconductive member through optical elements such as a collimator lens, polygonal scanner, f.theta. lens , reflection mirror and the like.
In the above laser scanning system, the respective optical elements, in particular, a semiconductor laser, cylindrical lens, polygonal scanner and f.theta. lens must be disposed with relative distance, relative angle and the like with pinpoint accuracy provided therebetween.
To achieve the aforesaid disposition, an optical scanning system is preferably composed of these optical elements, each the elements are disposed on a base member with a predetermined accuracy and mounted on the chassis of the imaging device as a unit. Such an assembly enhances workability in assembly and maintenance.
The base member is required to have a high rigidity so that it cannot be easily deformed, to thereby ensure that the relative distance, angle and the like between the respective optical elements are not disturbed.